Introduction to SQL – Real-Time Understanding

Just like we use language to communicate, databases also need a language to store, retrieve, and manage data. That language is SQL – Structured Query Language. It's used everywhere — from banks and hospitals to online stores and mobile apps.

Suppose you earn ₹1,00,000 per month. You spend on groceries, rent, petrol, school fees, etc. If you forget to track even one, your calculations go wrong. Now imagine running a business — missing employee salaries or client invoices can create chaos. Hence, we need structured data.

• Personal finance apps use databases to track your spending
• Businesses use databases to manage thousands of transactions
• Without organization, data becomes useless

You start a company in Hyderabad and expand to Bangalore, Chennai, and even abroad. Now you need to manage data from multiple branches — stock, sales, salaries, performance. That's where databases come in.

A small offer from Zomato can heavily affect Swiggy. Samsung reducing a phone's price may impact LG. Companies analyze historical data, track patterns, and decide strategy. This is data-driven decision-making.

YouTube sees 500+ hours of video uploaded every minute. Google handles billions of queries daily. They use massive databases to store, retrieve, and secure data. SQL is at the core of these operations.

In Oracle or other DBs, a schema is like a folder in your system. Just like Local Disk C or D, you can have schemas like SYSTEM, STAGE, SOURCE — each holding tables, procedures, etc.